Added API to get player's proxy address

[nostalfinals]

Introduction

This patch added an API to get the player's proxy address.
It will be useful if the server uses multiple proxy instances that support HAProxy Protocol (frp, nginx, etc.) and wants to know which proxy instance the player uses.

How?

I added a method, which is Player#getProxyAddress. This method returns an InetSocketAddress, if the server didn't enable Proxy Protocol, or the player didn't connect with an HAProxy instance, then it will return null.

Example

@EventHandler
fun playerJoinEvent(event: PlayerJoinEvent) {
    val player = event.player
    val proxyAddr = player.proxyAddress

    if (proxyAddr == null) {
        logger.info("Player ${player.name} didn't connect with a proxy!")
        return
    }

    logger.info("Player ${player.name} is using proxy: ${proxyAddr.hostString}:${proxyAddr.port}")
}

[github-actions]

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